Quick-action diaphragm-operated valve



2 Sheets-Sheet' 2 S. G. NEAL QUICK ACTVION DIAPHRAGM OPERATED VAALVE Filed May 27 1925 May 25 1926.

Patented May 25, 1926.

Unrrsn srares rarest Eo.ffriesg.

SPENCER G. NEAL, E NEw Yoan, N. Y., Ass'rGN'oRfTo AUT'oMAiiro STEAIG'HT A-in BRAKE COMPANY, 0E NEW CAsrLEDELAwAEE, A CORPORATION or DELAWARE.

"QUICK-ACTION DIAPHRAGM-OPERTED VALVE.

Application'led May 27, 1925. Serial No.. 33,182.

In apparatus where a valve, or other operating part or device, is moved through the operation of 'a dia hragm, and wherein the diaphragm is flexedj on opposite sides thereof, the movement of the diaphragm and the connected part is slow. rI`he valve is given what might be termed a creeping movement. This is due to the -fact that the diaphragm moves in response to the variations in pressures; as one pressure is decreased or increased below or Y quick or snap action in response to variations in the controlling pressures.

The invention is illustrated as applied to a type of triple valve for air bralre apparatus. This triple valve is fully described in my pending application for patent, Serial No. 9789, iiled February 17, 1925, certain features of that triple valve being omitted because it is unnecessary/to illustrate them in this case and in order to simplify the showing.

The invention may be applied to the triple valves illustrated in Patents Nos. 1,411,468 and 1,502,519, dated April 4, 1922, and July 22, 1924, respectively.

IVhile the invention is illustrated and described in connection with an air brake apparatus it is to be understood that it may be applied to any form of valve or devicel operated by a diaphragm and in which the movement of the diaphragm is brought about by establishing a difference in pressures on opposite sides oi the diaphragm.

In the drawings Fig. 1 is a diagrammatic view showing the invention applied to al triple valve for air brake ap aaratus, the "parts 'of the triple valve beingl shown in releaseposition; e

Fig. 2., diagrammatic sectional view dt the diaphragm structure showing the parts it. A quick-action ypostian,Y the: diaphragm by varying the pressures structure and the pilot` valve operated thereyby having made a partial movement toward service position;

Fig. 3 a view similar to Fig. 2 showing the parts in full service position;

Fig. 4 a view "similar to Fig. 2fshowing the pilotA graduating valve inservice lap-position; and

Fig, 5 a diagrammatic view el a portion of anY air brake apparatus.

Referring to Fig. 5 A designates an engine'ers brake valve; B a mainV reservoir; C a brake pipe; D a triple valve; E an auxiliary reservoir; F an emergency reservoir, and@ a brake cylinder.

The system yis charged by increasing the brake pipe pressure, as in the present standard Vilestinghouse-type of air brake apparatus. The air pressure 'from the brake pipe -llowsthrough the brake pipefconnection 2, the connected passage 3 into the' main piston chamber 1. rlhe increasing pressure i in chamber 1 forces the main piston 44 inwardly, toward the right hand as viewed'in the drawings. Connected to the piston is the usual valve stem 45, said stem extending inwardly through the main slide valve Chamber 5 and being connected tothe main slide valve 6 and the graduating valve 56 in the 'usual manner. The piston stemis connected to the main slide valve by a lost motion connection and thc graduating valve is connected directly to the saidv stem as is usual in this type of apparatus. The main slide valve operates on a main slide valve seat through which various ports and passages are formed. lVith the main piston infull release and charging positionfa charginggroove 4 is uncovered so that air may iow from 'chamber 1 through said groove past the piston 44 and into the main slide valve chamber 5. The main slide valve chamber is connected directlyto the auxiliary reservoir through passage 7. Thechamber- 5-is also connected to an emergency reservoir through passage 8, chamber 9 and a port controlled by a spring-pressed check valve 10. The 'spring a normally holds the Check valve seated and the rising pressurev in chamber 9 will unseat said valve and open communication between chamber 9 and the emergency-reselvoir; The auxiliary reservoir and the emergencyv reservoir will therefore be harged it the Sametime andat samerate. ehamber 1 breite "pipeA air ,Williiow tbreueh the passage 11 into an actuating chamber 12 of the diaphragm structure. The lower wall of chamber 12 is formed by an actuating diaphragm 13. Spaced a suitable distance below the diaphragm 13 is a larger equalizing diaphragm 53, said diaphragm being considerably larger in area than the actuating diaphragm 13. The diaphragms 13 and 53 form the upper and lower walls ot a bralre cylinder equalizing chamber 55. Below the equalizing diaphragm 53 is arranged a controlling diaphragm 16, this diaphragm being of the same area as the actuating diaphragm 13. Between the diaphragms 53 and 16 is formed a quick-action chamber` 26; and below the controlling d'aphragm 15 is formed a control pressure chamber 1'?. This latter chamber is connected to the emergency reservoir by passage 18 so that said chamber will be charged with emergency reservoir air.

The diapbragms 13 and 53 are rigidly connected together at their centers by a stem 13a and move up and down together. All of these diaphragme have a limited up and down movement, suitable stops being provided for that purpose. ln the brake cylinder equalizing chamber 55 is arranged a horizontal lever 15a which is pivetally connected to the stem 13a. One end of said lever is pivotally connected to the valve casing, its other end being operatively connected to a pilot valve 15 and to a graduating pilot valve 15", said valves being` arranged in a valve chamber 14. he lever 15L extends through -a slot in the valve 15, its end being directly connected to the graduating pilot valve 15b. The slot in the pilot valve permits of a limited independent movement ot the graduating valve and the graduating valve moves on the pilot valve for this limited distance. The pilot valve is held on its seat and the graduating pilot valve is held. to the pilot valve by any suitable yielding means. The chamber 14 is directly connected to the bralie pipe chamber 12 by a passage lele so that brake pipe chamber pressure will always be registered in the chamber 11i and the pressures in the chambers 12 and 14 will always be equal.

lith the triple valve parts in full release and charging position, with the release governing valve in quick release position, as shown in F ig. 1, the brake cylinder is in direct communication with atmosphere through brake cylinder passage 19, cavity 2O of the main slide alve, passage 21 which leads direct to the release governing valve chamber 22, and 'from this chamber to atmosphere through port 2S in the release govern ing valve 5?, and main atmospheric port 211.

The check valve 10 is opened l'or emergency applications ot the brakes by means oit a piston 8O and a lever 30a connected thereto and adapted to bear on the projecting end of the valve 10. The piston 30 reeiprocates in a chamber 30b and said chamber is charged from the main slide valve chamber through port 31 and cavity 31a in the main slide valve and port and passage 32 which leads from the main slide valve seat into chamber 30".

The piston 30 therefore is subject on one side chamber 1 will be reduced below the auXiliary pressure in chamber 5. The main and graduating valves will be moved toward the left by the superior auxiliary reservoir pressure in chamber 5. The initial movment of the piston and the stem -15 will "i first take up the lost motion between the cxtension 46 of the stem and the main slide valve. This initial movement will also more the graduating valve to uncover he service port t9 in the main slide valve. Thereafter the main slide valve will move with the piston stem until the piston engages the gradi'.- ating stem 47 where it will be stopped iu service position. The movement of the main slide valve to service position closes communication between the brake cylinder passage 19 and the release cavity 2O of the slide valve 6, andthe service port 19 is brought into register with the brake cylinder passage 19. Auxiliary reservoir air is then tree to flow from chamber 5 direct to the bralle elinder through passage 50 in the stem 1, port 49 of the main slide valve and the brano cylinder passage 19 which leads direct to the brake cylinder. The brake cylinder will be connected to the equalizing` chamber o the pilot valve structure through passage 5l, cavity 6l of the main slide valve and pas4 sage 52 which leads direct to chamber rThis communication permits the supplementary or pilot valve to both supply and lc lease air from the brake cylinder so lungi' as the main slide valve (l is iu ser fice position.

The reduction of brake pipe pressure iu chamber 1 will result in a correspondiuff u duction of pressure in the actuating cha 12 ot' the diaphragm structure. resulting iu an upward movement oli the diapnr. structure. This up 'ard movementH ref-zu from the reduction of the pressure in chasuber 12 below the undisturbed emergency rcs44 ervoir pressure in chamber ll beneath the diaphragm 16.

The lever 15 will be carried upwardly aud the graduating pilot valve will be moved iudependently of the pilot valve 15 until the lever reaches the upper end of the slot in the pilot valve. This independent movement ot the graduating pilot valve will place port 29 ot said valve in register with port 29 ol the pilot valve. This movement of the graduating pilot valve will uncover quickaction port 25 ot the pilot valve. The continuetL upward movement ot the diaphragm structure and lever a will now move the two valves together and bring port into communication with port 27 leading into the quick-action chamber 2G. Quick action chamber 2G will now be in direct communication with the chamber 1drand brake pipe air will flow directly into said chamber. The flow ot brake pipe air directly into chamber 2G of the diaphragms becauseof the large area of diaphragm 53. The pressure in chamber 2G will assist the undisturbed emergency reservoir pressure in chamber' 17 to t' ree the diaphragm structure and the pilot valve to full service position. The flow of air into chamber 26 gives a quick impulse to the diaphragm structure and carries the pilot valve to service position with a quick snap action. The movement of the pilot valve from quickaction position, as shown in Fig. 2, to ul'l service position, as shown in Fig. 3, will cause the pilot valve to close port 27 and to bring port 29'Cl into communication with the chamber 55. Port 27 is closed before the port 29a is fully opened so that the tlow ot air into chamber 25 is stopped before brake cylinder pressure starts to build up in chamber 55. Chamber 26 is provided with an atmospheric leak port 28 so that the air that flowed into chamber 26 through port 2.7 may leak down to atmosphere through port 28. The purpose of this is to remove the pressure from chamber 26 so that it will not influence or aiiect the build-up ot brake cylinder pressure in the brake cylinder equalizing chamber55. Then the pilot valve 15 has been moved upwardly into service position brake pipe air will flow to the brake cylinder through port 29 in the pilot valve, equalizingl chamber 55, passage 52, cavity 64 of the main slide valve and passage 51 which leads direct into the brake cylinder passage 19. lt is therefore clear that in the service position ot the main slide valve air will flow to the brake cylinder :trom auxiliary r'servoir through the main slide valve and also from the brake pipe to the brake cylinder through the independent pilot valve.

rihe means which establishes the dual comnuinication between the auxiliary reservoir and the brake cylinder, and the brake4 pipe and the brake cylinder, are lapped independently o1 each other. The main valve means controlling` communication between the auxiliary reservoir and the brake cylinder will be operated to the right to cause the graduating valve to cut 011 communica tion between chamber 5 and port 1.19 of the slide valve when the pressure in chamber 5 has been reduced slightly below the brake will result in a quick upward movement.

pipe pressure in chamber 1. The connection `between the brake pipe and the brake cylin der controlled by the secondary valve means is closed when a given brake cylinder pressure has been developechthis .pressure being regi. tered at all times in trie equalizingchamber 55, and when this pressure is raised to a.

to the diaphragme 13 and 16 that the desired brake cylinder pressure will be built up inthe brake cylinder before the graduating pilot valve will bemoved to lap position. rilhis diaphragm is larger than the diaphragme 13 and 1G and preferably is so proportioned that the brake cylinder pressure will be built up two and one halt1 times the amount ot the brake pipe reduction, that is to say., for a ten pound brake pipe reduction a twenty-live pound brake cylinder pressure will be built up betere the graduating pilot valve is moved to lap position. rlhe movement of the graduating pilot valve to lap position closes the quicloaction port 25.

A release ot brake cylinder pressure is obtained by increasing the brake pipe pres sure through the b alte valve A in the usual manner, thereby increasing the pressures in chambers 1 and 12. r[he increase of pressure in chamber 1 will move the main piston and the main and graduating valves to lrelease position as shown in F ig. 1. rlllhe increase oiz pressure in chamber 12 will move the diaphragm structure downwardly and will carry the pilot valve and the graduating pilot valve to release position. The quickaction port will pass over the port 27 but no air will be admitted to the quickaction chamber 26 because the graduating pilot valve has closed the quick-action port 25, and this port remains closed during the movement ot the pilot valve from service position to release position'. ln the release position of the pilot valve the equalizing chamber 55 will be connected to atmosphere through cavity 61 ot the pilot valve, passage 62, cavity -ll ot the main slide valve and atn'iospheric port 12.

The chamber 17 is shown in Fig. 1 as connected to an emergency reservoir. 1t is manitest that the operating pressure may be established in chamber 17 in any suitable manner and that it is not necessary to conn neet said chamber to an emergency reservoir. In Fig. 3 the chamber 17 is connected to chamber 12 by a by-pass passage 63 and in this lpassage is arranged a back-pressure "JX l...

check valve (i5. In this arrangement the chamber 17 will be charged from the chamber 12 and Will be maintained at the maximum pressure established in chamber 12. This will provide a substantially constant operating` pressure in chamber 17'.

.The release governing` valve 57 is fully described in my co-pendinp; application Serial No. 9789, hereinbefore referred to. The graduated `release operations ot the diaphragm structure and the pilot valve, and the compensating' operation of' the pilot ralve, are also fully described in the said co-pending; application and need not be described herein. The means for varying;r the pressure in the actuating; chamber 12 is the usual engineers b alte valve commonly used on all air brahe apparatus and it is thought to be unnecessary to illustrate and describe it herein. The pressure in the actuatingY chamber may be varied aud controlled by any suitable valve mechanisms.

ii/That l claim is:

1. A diaphragm-operated device compris-v ing' a casing', an actuating' diaphragm therein 'Forming' an actuatingr chamber, an equalizingr diaphragm larger in area than the actuatine' diaphragm, a controlling diaphragm smaller in area than the equalizing diaphragm and termina' a quick-action chamber bet-Ween the eaual'zing diaphragm and the controlling diaphragm and torming a control pressure chamber between the controlling' diaphragm and the casing', means ttor establishing an operating pressure in the control pressure chamber, means tor varying' the pressure in the actuating chamber. means actuated by the diaphrzfipgms when said diaphragms moved toward the actuating chamber te admit, fluid pressure into thev quick-action chamber to assist the pressure in the control pressure chamber in unV .nx-o; the diaphragms toward the actuati l chaniber, and a (.evice adapted to be operated by said diaphragms when they are moved by the pressures in the control pres` sure chamber and in the equahZing-j chamber.

2. i diaphrapjn'l-operated valve comprising' a an actuating' d' rjm therein toi iV Y n equalizina' diaphragm larger in than the actuating diaphragm and `torn'iine' au equalizchamber, a controlling: diaphracjm smaller in arca. than the equalizing' diaphragm and 'Forming` a quick-action chamber between the equalizing diaphragm and the controlling diaphragm and forming a control pressure chamber between the controlling' diaphragm and the casing, means tor establishing' au operating pressure in the control pressure chamber, means for varying the pressure in the actuatingl chamber, means actuated by the diaphragme when saidrdiaphragms are moved toward the actin ating chamber to admit Huid pressure into the quick-action chamber to assist the pressure in the control pressure chamber in moving the diaphragms toward the actuating chamber, and a rali-e adapted to be operated by said diaphragins when they are moved by the pressures in the control pr ssure chamber and in the equalizing chamber,

3. A diaphrae'm-operated device comprising a casing, an actuating diaphragm therein forming an actuating chamber, an equalizing diaphragm larger in area, than thc actuating' diaphragm, a controlling diaphragm smaller in area than the equalizing; diaphragm and vforming a quick-action chamber between the equalizinp,l diaphragm and, the controlling diaphragm and termine' a control pressure chamberv between the tontrolling diaphragn'i andthe casing', means For establishing au operating' pressure in the control pressure chalnber, means for varying' the pressure vin the actuating chamljrer, a valve actuated by the diaphragms When diaphragme are moved toward the actuating; chamber to admit tluid pressure into the quick-action chamber to assist the pressure in the control `pressure chamber iu n'ioyiug the diaphragme toward the actuating cham` bei', and a device adapted to be operated by said diaphragme when they are moved hy the pressures in the control pressure chainber and in the eipializiup,` chamber.

il. A diapliraam-operated device comprising' diaphragm. means lier subjecting; said diaphragm to substantially vequal opposed pressures, means for varying one ol said pressures to causethc diaphragm to move toward the low r pressure. means operated by the movement ot said diaphragm to ,Qjive to tie diaphragm a Quick impulse toward the lower pressure. and means operate( by the quick action oi"- said diapln'ae'n'i.

5. A diaphragni-operated .evice comprising; a diaphragm, means 'for subjecting said diaphragm to opposed pressures, means 'tor varying; one oi said pressures to cause the diag. rin to more toward the lower pressure, fluidv pressure nica oi erated by the increment oii said diaphragm to rive to the diaphragm a quiet: impulse toward the louer pressure, and n'ieaus operatexl by the quiclr action or said diaphragm.

6. A d .rihragm-operated device comprising' a diaphragm, means 'ter subjectin fard diaphragm to substantially equal opposed pressures, means for reducing' one ol said pressures to cause the diaphragmL to move toward the reducedV pressure, tluid pressure means operated by the movement et said diaphragm to 2Qive to the' diaphragm a quick impulse toward the reduced pressure, and means operated by the quick action ot said diaphragm.

7. A diaphragm-operated device comprisa diaphragm, means Jfor subiccn diaphragm to substantially equal opposed pressures, means ior reducing one ot said pressures to cause the diaphragm to move toward the reduced pressure, fluid pressure means' operated by the n'ioven'ient ci said diaphragm to give to the diaphragm a quichr impulse toward the reduced pressure, and a valve operated to iinal position by the quick action ot' said diaphragm.

8. A diaphragm-operatcd device comprising a diaphragm, means for subjecting said diaphragm to substantially equal opposed pressures, means 'for reducing one ot said pressures to cause the diaphragm to move toward the reduced pressure, fluid pressure means operated by the movement oi said diuphragn'i to give to the diaphragm a quick impulse toward the reduced pressure, and u valve operated to open position by the quick action of said diaphragm.

9. A diaphragm-operated device comprising a casing, an actuating diaphragm therein forming an actuatingl chamber, an equalizing diaphragm larger in area than the actuating diaiihragm and Yharming an equalizing chamber, a controlling dial'ihragm ,smaller in area than the equalizing .diaphragm and forming a quick-action chamber between the equalizing diaphragm and the controlling diaphragm and forming a control pressure chamber between the controlling diaphragm and the casing, means ior establishing an operating pressure in the control pressure chamber, means for varying the pressure in the actuating chamber, a pilot valve and a graduating pilot valve actuated by the diaphragms when said diaphragme are moved toward the actuating chamber to admit fluid pressure into the quick-action chamber to assist the pressure in the control pressure chamber in moving the diaphragms toward the actuating chamber, the pilot valve being` operated by said diaphragms when they are moved by the pressures in the control pressure chamber and inthe quick-action chamber to admit air into the equalizing chamber and to stop the How of fluid under pressure into lthe quick-action chamber.-

10. A diaphragua-operated device comprising a casing, an actuating diaphragm. therein forming an actuating chamber, an

equalizing diaphragm larger in area than the actuating diaphragm and forming an equalizing chamber, a controlling diaphragm smaller in area than the equalizing diaphragm and forming a quick-action chamber between the equalizing diaphragm and the controlling diaphragm and forming a control pressure chamber between the controlling diaphragm and the casing, means for establishing an operating pressure in the control pressure chamber, means for varying the pressure in the actuating chamber, a pilot valve and a graduating pilot prising a ralve actuated by the diaphragms when said diaphragms are moved toward the actuating chamber to admit fluid pressure into the quick-action chan'iber to assist the pressure in the control pressureY chamber iu moving the diaphragms toward the actuating chan'iber, the pilot valve being operated by said diaphragins when they are moved by the pressures in the control pressure chamber and in the quick-action chamber to admit air into the equalizi. chan'iber and to step tl w llow ot 'fluid under pro :re into the (prim-action chamber, and meansI to perii i i 'c in the quick-action uber to blow down to atmosphere. A diaphragni-operated device valves for air bralre appar Ltus conipri. g a casing, an actuating diaphragm therein forming an actuating chamber, an equalizing diaphragm larger in area than the actuating` diaphragm and forming an equalizing chamber, a controlling diaphragm smaller in area than the equalizing diaphragm and i'orming a quick-action chamber between the equalizing diaphragm and the controlling diaphragm and forming a control pressure chamber between the coutrolling diaphragm and the casing, means ccnnccting the actuating chamber to a brake pipe, means connecting the equalizing chamber to a brale cylinder, means connecting the control pressure chamber to an emergency reservoir, means for varying the vpressure in the actuating chamber, a valve actuated by the diaphragms when said diaphragme are moved toward the actuating chamber to admit brake pipe pressure into the quick-action chamber to assistthe pressure in the control pressure chamber in moving the diaphragms toward the actuating chamber, and a valve adapted to be operated by said diaphragms when they are moved by the pressures in the control pressure chamber and in the equalizing chamber to admit brake pipe air into the equalizing 'ch amber.

A diaphragm-operated device for triple valves for air brake apparatus comcasing, an actuating diaphragm therein forming an actuating chamber, an equalizing` diaphragm larger in area than the actuating diaphragm and forming an equalizing chamber, a controlling diaphragm smaller in than the equalizing diaphrag n and forming a quick-action cham-V ber between the equalizing diaphragm and the controlling diaphragm and forming a control pressure chamber between the controlling diaphragm and the casing, means connecting the actuating chamber to a brake pipe, means connecting the equalizing chamber to a brake cylinder, means connecting the control pressure chamber to an emergency reservoir, a valve actuated by the diapliragmg when said diaphragms are "vi u moved to `fard the actuating chamber to admit pressure into the quick-action chamber to assi the pressure in the control pressure c i mber in moving the diaphragms toward tue actuating clian'iber, and a valve adapted to be operated` by said diaphragms when they are moved by the pressures in the centr-oi pressure chamber and in the chamber to admit air into the equalii/:iug chamber.

i3. A triple valve for air brake apparatus comprising a casing, a main slide valve, a piston connected thereto and adapted to more in response to variations in brake pipe prssure, an actuating di: phragm forming an actuating chamber, an equalizing diaphragm larger in area than the .actuating diaphragn'i and forming an equaiizing chamber, a controliing diaphragm smaller in area than the equalizing diaphragm and forming a quick-action chamber between the equalizing diaphragm and the controlling diaphragm and iforn'iing a control pressure chamber between the con trolling diaphragm and the casing, means connecting the actuating chamber to a brake pipe, means connecting the equalising chamber to a brake cylinder, means connecting the control pressure chamber to an emergency reservoir, a valve actuated by the diaphragms when said diaphragms` are .loved toward the actuating chamber to admit air under pressure into the quickaction chamber to assist the pressure in the control pressure chaml er in moving the diaphragms toward the actuating chamber, and a valve adapted to be operated by said diaphragme when they are moved by the pressures in the control pressure chamber and in the equaiizing chamber to admit air into the equalizing chamber.

lli. A triple valve l'or air brakek apparatus comprising a casing, a main slide valve, a piston connected thereto and adapted to move in response to variations in brake pipe pressure, an actuating diaphragm forming an actuating chamber, an equalizing diaphragm larger in area than the actuating diaphragm and forming an equalizing chamber, a controlling diaphragm smaller in area than the equalizing diaphragm and forming quick-action chamber between the equalizing diaphragm and the controlling diaphragm .and forming a control pressure chamber between the controlling diaphragm and the casing, means Connecting the aetu ating chamber to a brake pipe, means cunnecting the equalizing chamber to a brake cylinder, means connecting the controi presH sure chamber to an emerge cy reservoir, a pilot valve and a graduating pilot valve actuated by the diaphragms when said diaphragms are moved slightly toward the actuating chamber to admit air under pressure into the quick-action chamber the said valves being operated by said diaphragnis 'when they are moved to linal positions by the pressures in the control pressure chamber and in the equalizing chamber to admit air into the equalizing chamber and to stop the iew of air into the quick-action chamber, and means to permit the air in the quick-action chamber to iow to atmosphere.

15. A diaphragm-operated device for a triple valve for air brake apparatus comprisin a diaphragm, means for subjecting said diaphragm to opposed pressures troni the brake pipe, a brake cylinder and an emergency reservoir, means for reducing the brake pipe pressure to cause the diaphragm to move toward the reduced brake pipe pressure, means operated by the movement oi said diaphragm to give to the diaphragm a quick impulse toward the reduced brake pipe pressure, and means operated by the quick action ot said diaphragm to admit air to a brake cylinder.

16. A triple valve for air brake apparatus comprising a Casin-g, a main slide valve, a piston connected thereto and adapted to move in response to a reduction in brake pipe pressure to connect an auxiliary reservoir to a brake cylinder, a diaphragm, means for subjecting said diaphragm to opposed pressures from the brake pipe, a brake cylinder and an emerge cy reservoir and operating upon a reduction 01" brake pipe pressure to cause the diaphragm to more toward t ie reduced brake pipe pressure, means operated by a slight movement of said diaphragm to give to the diaphragm a quick impulse toward the reduced brake pipe pressure, and means operated by the iinal quick action of said diaphragm to admit brake pipe air to a brake cylinder.

In testimony whereof I hereunto aiiix my signature.

SPENCER G. NEAL. 

